The role of MRI in perianal fistulizing disease: diagnostic imaging and classification systems to monitor disease activity.

Perianal fistulizing disease, commonly associated with Crohn's disease, poses significant diagnostic and therapeutic challenges due to its complex anatomy and high recurrence rates. Radiological imaging plays a pivotal role in the accurate diagnosis, classification, and management of this condition. This article reviews the current radiological modalities employed in the evaluation of perianal fistulizing disease, including magnetic resonance imaging (MRI), endoanal ultrasound, and computed tomography (CT). MRI, recognized as the gold standard, offers superior soft tissue contrast and multiplanar capabilities, facilitating detailed assessment of fistula tracts and associated abscesses. CT, although less detailed than MRI, remains valuable in acute settings for detecting abscesses and guiding drainage procedures. This article discusses the advantages and limitations of each modality, highlights the importance of standardized imaging protocols, and underscores the need for interdisciplinary collaboration in the management of perianal fistulizing disease. Future directions include advancements in imaging techniques and the integration of artificial intelligence to enhance diagnostic accuracy and treatment outcomes.

Impact of timing of primary ileocecal resection on prognosis in patients with Crohn's disease.

BACKGROUND: The advantage of early ileocecal resection after Crohn's disease diagnosis is a matter of debate. This study aims to assess the timing of ileocecal resection on prognosis, after correction for possible confounders. METHODS: Patients with Crohn's disease with primary ileocecal resection between 2000 and 2019 were included in a retrospective multicentre cohort. The primary endpoint was endoscopic recurrence (Rutgeerts score ≥i2b) within 18 months. Secondary endpoints were escalation of inflammatory bowel disease medication within 18 months and re-resection during follow-up. The association between timing of ileocecal resection and these endpoints was investigated using multivariable proportional hazard models, corrected for covariates including Montreal classification, postoperative prophylaxis, smoking, indication for surgery, medication before ileocecal resection, perianal fistulas, surgical approach, histology, length of resected segment and calendar year. RESULTS: In 822 patients ileocecal resection was performed after a median of 3.1 years (i.q.r. 0.7-8.0) after Crohn's disease diagnosis. The lowest incidence of endoscopic recurrence, escalation of inflammatory bowel disease medication and re-resection was observed for patients undergoing ileocecal resection shortly after diagnosis (0-1 months). After correction for covariates, patients with ileocecal resection at 0, 4 and 12 months after diagnosis had a cumulative incidence of 35 per cent, 48 per cent and 39 per cent for endoscopic recurrence, 20 per cent, 29 per cent and 28 per cent for escalation of inflammatory bowel disease medication and 20 per cent, 30 per cent and 34 per cent for re-resection, respectively. In the multivariable model ileocolonic disease (HR 1.39 (95 per cent c.i. 1.05 to 1.86)), microscopic inflammation of proximal and distal resection margins (HR 2.20 (95 per cent c.i. 1.21 to 3.87)) and postoperative prophylactic biological and immunomodulator (HR 0.16 (95 per cent c.i. 0.05 to 0.43)) were associated with endoscopic recurrence. CONCLUSION: The timing of ileocecal resection was not associated with a change of disease course; in the multivariable model, the postoperative recurrence was not affected by timing of ileocecal resection.

Prophylactic Medication for the Prevention of Endoscopic Recurrence in Crohn's Disease: a Prospective Study Based on Clinical Risk Stratification.

BACKGROUND: To prevent recurrence after ileocolonic resection [ICR] in Crohn's disease [CD], postoperative prophylaxis based on risk stratification is recommended in international guidelines. This study aimed to evaluate postoperative CD recurrence after implementation of a clinical management algorithm and to determine the predictive value of clinical and histological risk factors [RFs]. METHODS: In this multicentre, prospective cohort study, CD patients [≥16 years] scheduled for ICR were included. The algorithm advised no postoperative medication for low-risk patients, and treatment with prophylaxis [immunosuppressant/biological] for high-risk patients [≥1 RF: active smoking, penetrating disease, prior ICR]. Clinical and histological RFs [active inflammation, granulomas, plexitis in resection margins] for endoscopic recurrence [Rutgeerts' score ≥i2b at 6 months] were assessed using logistic regression and ROC curves based on predicted probabilities. RESULTS: In total, 213 CD patients after ICR were included [age 34.5 years; 65% women] (93 [44%] low-risk; 120 [56%] high-risk: 45 [38%] smoking; 51 [43%] penetrating disease; 51 [43%] prior ICR). Adherence to the algorithm was 82% in low-risk [no prophylaxis] and 51% in high-risk patients [prophylaxis]. Endoscopic recurrence was higher in patients treated without prophylaxis than with prophylaxis in both low [45% vs 16%, p = 0.012] and high-risk patients [49% vs 26%, p = 0.019]. Clinical risk stratification including the prescription of prophylaxis corresponded to an area under the curve [AUC] of 0.70 (95% confidence interval [CI] 0.61-0.79). Clinical RFs combined with histological RFs increased the AUC to 0.73 [95% CI 0.64-0.81]. CONCLUSION: Adherence to this management algorithm is 65%. Prophylactic medication after ICR prevents endoscopic recurrence in low- and high-risk patients. Clinical risk stratification has an acceptable predictive value, but further refinement is needed.

Stromal vascular fraction with platelet-rich plasma injection during surgery is feasible and safe in treatment-refractory perianal fistulising Crohn's disease: A pilot study.

BACKGROUND: An unmet need remains for improved management in perianal fistulising Crohn's disease (pCD). Recently, local administration of adipose-derived cells has shown promising results. AIMS: To assess the safety and feasibility of injection of stromal vascular fraction (SVF) with platelet-rich plasma (PRP) in patients with pCD. METHODS: Patients ≥ 18 years with pCD were included and underwent fistula curettage, SVF with PRP injection, and closure of the internal opening. The primary endpoint was safety at 12 months. The secondary outcomes were complete radiological healing at 3 months (absence of fluid-containing tracts on MRI) and partial and complete clinical response at 3 and 12 months (closure of ≥1, respectively, all treated external opening(s)). RESULTS: Twenty-five patients were included (35 [IQR 25-40] years; 14 [56%] female); median CD duration 4 [IQR 2-8] years. Twenty-four (95%) patients had previously undergone fistula surgery. No adverse events were encountered at lipoharvesting sites. Two (8%) patients were readmitted to hospital and six (24%) underwent unplanned re-interventions. Post-operative MRI (n = 24) showed complete radiological healing in nine (37.5%) patients. Partial clinical response was present in 48% (12/25) at 3 months and in 68% (17/25) at 12 months, and complete clinical closure in five (20%) patients at 3 months and in 10 (40%) patients at 12 months. CONCLUSION: Injection with autologous SVF with PRP is feasible and safe in patients with treatment-refractory pCD. Early complete radiological healing was observed in more than one-third of patients, and clinical response in two-thirds of patients at 12 months.

Risk Prediction and Comparative Efficacy of Anti-TNF vs Thiopurines, for Preventing Postoperative Recurrence in Crohn's Disease: A Pooled Analysis of 6 Trials.

BACKGROUND & AIMS: The superiority of anti-TNF-α agents to thiopurines for the prevention of postoperative recurrence of Crohn's disease (CD) after ileocolonic resection remains controversial. In this meta-analysis of individual participant data (IPD), the effect of both strategies was compared and assessed after risk stratification. METHODS: After a systematic literature search, IPD were requested from randomized controlled trials investigating thiopurines and/or anti-TNF-α agents after ileocolonic resection. Primary outcome was endoscopic recurrence (ER) (Rutgeerts score ≥i2) and secondary outcomes were clinical recurrence (Harvey-Bradshaw Index/Crohn's Disease Activity Index score) and severe ER (Rutgeerts score ≥i3). A fixed effect network meta-analysis was performed. Subgroup effects were assessed and a prediction model was established using Poisson regression models, including sex, smoking, Montreal classification, CD duration, history of prior resection and previous exposure to anti-TNF-α or thiopurines. RESULTS: In the meta-analysis of IPD, 645 participants from 6 studies were included. In the total population, a superior effect was demonstrated for anti-TNF-α compared with thiopurine prophylaxis for ER (relative risk [RR], 0.52; 95% confidence interval [CI], 0.33-0.80), clinical recurrence (RR, 0.50; 95% CI, 0.26-0.96), and severe ER (RR, 0.41; 95% CI, 0.21-0.79). No differential subgroup effects were found for ER. In Poisson regression analysis, previous exposure to anti-TNF-α and penetrating disease behavior were associated with ER risk. The advantage of anti-TNF-α agents as compared with thiopurines was observed in low- and high-risk groups. CONCLUSIONS: Anti-TNF-α is superior to thiopurine prophylaxis for the prevention of endoscopic and clinical postoperative CD recurrence after ileocolonic resection. The advantage of anti-TNF-α agents was confirmed in subgroup analysis and after risk stratification.

Indications, Postoperative Management, and Long-term Prognosis of Crohn's Disease After Ileocecal Resection: A Multicenter Study Comparing the East and West.

BACKGROUND: The Crohn's disease (CD) phenotype differs between Asian and Western countries and may affect disease management, including decisions on surgery. This study aimed to compare the indications, postoperative management, and long-term prognosis after ileocecal resection (ICR) in Hong Kong (HK) and the Netherlands (NL). METHODS: CD patients with primary ICR between 2000 and 2019 were included. The endpoints were endoscopic (Rutgeerts score ≥i2b and/or radiologic recurrence), clinical (start or switch of inflammatory bowel disease medication), and surgical recurrences. Cumulative incidences of recurrence were estimated with a Bayesian multivariable proportional hazards model. RESULTS: Eighty HK and 822 NL patients were included. The most common indication for ICR was penetrating disease (HK: 32.5%, NL: 22.5%) in HK vs stricturing disease (HK: 32.5%, NL: 48.8%) in the NL (P < .001). Postoperative prophylaxis was prescribed to 65 (81.3%) HK patients (28 [35.0%] aminosalicylates [5-aminosalicylic acid]; 30 [37.5%] immunomodulators; 0 biologicals) vs 388 (47.1%) NL patients (67 [8.2%] 5-aminosalicylic acid; 187 [22.8%] immunomodulators; 69 [8.4%] biologicals; 50 [6.1%] combination therapy) (P < .001). Endoscopic or radiologic evaluation within 18 months was performed in 36.3% HK vs 64.1% NL (P < .001) patients. No differences between both populations were observed for endoscopic (hazard ratio [HR], 0.53; 95% confidence interval [CI], 0.24-1.21), clinical (HR, 0.91; 95% CI, 0.62-1.32), or surgical (HR, 0.61; 95% CI, 0.31-1.13) recurrence risks. CONCLUSION: The main indication for ICR in CD patients is penetrating disease in HK patients and stricturing disease in NL patients. Although considerable pre- and postoperative management differences were observed between the two geographical areas, the long-term prognosis after ICR is similar.

This is the first study reporting similar long-term prognoses after ileocecal resection in Crohn's disease in low- and high-incidence countries despite differences in Crohn's disease phenotype at diagnosis, surgical approach, indications, and pre- and postoperative management including prophylactic medication.